Using television signals, for example, a channel may carry both video and audio components of a broadcast occupying about six megahertz of the VHF frequency spectrum. For the purpose of this disclosure, a “channel” is defined as one or more related device components that respond over a particular frequency band. Further, a “channelizer” is a multi-channel device that may receive incoming signals, separate the incoming signals into a plurality of different channels based upon the frequency range of each individual channel, and provide the individual channels to some other device.
A traditional approach to creating a linear version of the channelizer is to directly digitize the signal using high-speed and highly accurate, i.e. having lots of bits, analog-to-digital converters (ADCs). The signal is then processed using dedicated digital signal processing hardware. Due to speed and accuracy limitations, many ADCs may be required to digitize ‘chunks’ of the spectrum in parallel. Although this approach is straight forward, and offers some significant benefits in performing specific functions (such as processing correlated spread spectrum signals that are below the ambient noise level), the resulting systems tend to be large, expensive, and power consuming. This makes them impractical for applications such as man-portable systems, which need to be compact, lightweight and power efficient.
While there is a strong effort within the engineering and scientific communities to develop high-speed, high-accuracy ADCs for such purposes, the low-power and low-cost devices needed to meet current signal processing needs remain elusive. Accordingly, new approaches to channelizing are desirable.